Method for making a recess or opening into a planar workpiece using successive etching

Abstract

A method for making a recess or opening in a planar workpiece with a thickness of less than 3 millimeters includes successively etching a plurality of flaws to form the recess or opening such that a contour of the recess or opening has a sequence of widenings and constrictions as a result of the etching.

What is claimed is: 
     
         1 . A method for making a recess or opening in a planar workpiece with a thickness of less than 3 millimeters, the method comprising:
 successively etching a plurality of flaws to form the recess or opening having a diameter and a cross-section, such that the cross-section of the recess or opening has a sequence of widenings and constrictions of the diameter as a result of the etching,   wherein the widenings, as viewed in the cross-section, have different concave arcuate shapes between adjacent ones of the constrictions.   
     
     
         2 . The method according to  claim 1 , wherein the sequence of widenings and constrictions include at least one widening that has a different maximum diameter relative to an adjacent one of the widenings, and/or at least one constriction that has a different minimum diameter relative to an adjacent one of the constrictions. 
     
     
         3 . The method according to  claim 1 , wherein the sequence of widenings and constrictions include at least one widening and constriction that have a different spacing in a direction of extension of the recess or opening relative to an adjacent one of the widenings and constrictions. 
     
     
         4 . The method according to  claim 1 , wherein the widenings and/or the constrictions have center points which do not lie on a same straight line. 
     
     
         5 . The method according to  claim 1 , wherein the widenings and/or the constrictions are arranged offset to one another. 
     
     
         6 . The method according to  claim 5 , wherein the widenings and/or the constrictions have center points which lie on a same straight line that is inclined relative to a surface normal of the workpiece. 
     
     
         7 . The method according to  claim 1 , wherein heights of adjacent ones of the widenings differ from one another in a direction of extension of the recess or opening. 
     
     
         8 . The method according to  claim 1 , wherein a total surface area of at least one of the widenings between adjacent ones of the constrictions differs from a total surface area of an adjacent one of the widenings. 
     
     
         9 . The method according to  claim 1 , wherein the sequence of widenings and constrictions extends across an entire thickness of the workpiece so as to form the recess or opening as a through-hole. 
     
     
         10 . The method according to  claim 1 , further comprising forming the flaws by a sequence of pulses or a single pulse of laser radiation. 
     
     
         11 . The method according to  claim 10 , wherein the sequence of pulses or the single pulse of laser radiation comprises a spatial beam that reacts across an entire thickness of the workpiece. 
     
     
         12 . The method according to  claim 11 , wherein the flaws are formed as a chain of blisters that are separated from each other along the chain. 
     
     
         13 . The method according to  claim 12 , wherein the chain of blisters extends across an entire thickness of the workpiece. 
     
     
         14 . The method according to  claim 13 , wherein, during the successive etching, etching fluid enlarges each of the blisters until breaking through into the next blister along the chain until all of the blisters have been connected to form the recess or opening as a through-hole. 
     
     
         15 . The method according to  claim 12 , wherein, during the successive etching, etching fluid enlarges each of the blisters until breaking through into the next blister along the chain until all of the blisters have been connected to form the recess or opening. 
     
     
         16 . The method according to  claim 1 , wherein heights of the concave arcuate shapes in a direction of extension of the recess or opening are different relative to one another. 
     
     
         17 . The method according to  claim 1 , wherein a maximum distance from the concave arcuate shapes to a center axis of the recess or opening are different relative to one another. 
     
     
         18 . The method according to  claim 1 , wherein the sequence of widenings and constrictions form an earthworm shape of the recess or opening. 
     
     
         19 . The method according to  claim 1 , wherein the planar workpiece is formed from glass. 
     
     
         20 . The method according to  claim 19 , further comprising forming the flaws by a single pulse of laser radiation that comprises a spatial beam that reacts across an entire thickness of the workpiece.